Friction sander. By The Shed and Beyond. 9:06 video:
https://www.youtube.com/watch?v=w-yFcS-f_cY
Previously:
https://www.homemadetools.net/forum/...232#post161348
https://www.homemadetools.net/forum/...240#post154023
https://www.homemadetools.net/forum/...498#post151231
